Nothing that springs to mind, you don't appear to be doing anything unusual. Could you try the same command and add "--debug all=all" to the command line and send me the output, I'll see if I can see anything. One quick thing to check is that the ompi-ps command is giving the correct output, this should contain the hostname and pids of each of your processes, you could check this is correct and send me the output as well to check the format hasn't changed again.

The 3.2 beta release of padb is proving very good, it's purely time that's stopped me turning the handle and making it a fully fledged release so you should try this to see if it makes a difference to your problem. The website for padb (containing links to it's own mailing lists) is in my signature.